dacite definition by American Heritage Dictionary
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A light gray volcanic rock containing a mixture of plagioclase and other crystalline minerals in glassy silica, similar in appearance to rhyolite.
Origin: After Dacia.
dacite - Science Definition
A fine-grained light gray volcanic rock consisting primarily of quartz, plagioclase feldspar, and potassium feldspar, and also containing biotite, hornblende, or pyroxene. It is the fine-grained equivalent of granodiorite.